This invention relates generally to locking devices, and in particular to a method and device for the prevention of tampering with cable locking devices.
An example of a prior art cable lock 100 is depicted in FIG. 12. The cable lock includes an outer member 101 surrounding an inner member 102. A pair of channels 104a and b are defined between inner and outer members 102 and 101, and a cable 106 is inserted into channels 104a and b. Cable 106 is locked in place in channel 104a by a disk 108 positioned on a ramp 110 defined on inner member 102. Prior to insertion of cable 106 into channel 104a, disk 108 is biased toward a top end 112 of ramp 110 by a spring 114. The insertion of cable 106 forces disk 108 down ramp 110. If cable 106 is then retracted in a direction 118 shown in FIG. 12, disk 108 squeezes cable 106 and prevents its removal. A more detailed disclosure of the prior art depicted in FIG. 12 can be obtained in U.S. Pat. No. 5,611,583.
It has been discovered that prior art cable locks, such as cable lock 100 discussed above, suffer from several disadvantages. One of these disadvantages is the ease in which the presence of these security locks can be identified. These cable locks are often used to secure the contents of rail cars, semi-trucks, or other like vehicles. During the night-time hours, it can be a difficult and time-consuming job to check for the presence of these security locks on a vehicle, especially when there are numerous vehicles, as in the case of a train comprising a large number of rail cars. In the past, a person checking for the presence of these security devices has had to provide his or her own light source, such as a flashlight, and aim the light precisely at the lock in order to identify whether a security lock is present or not. This task can prove to be undesirably time consuming.
Another disadvantage of past cable locks are their susceptibility to being tampered with by determined thieves. The tampering occurs in one of two general ways. First, a hole may be drilled generally through a wall 116 located at an end of cable lock 100 (FIG. 12). The hole is drilled oriented toward disk 108. After completely drilling through wall 116, a pin or other suitable instrument is inserted into the drilled hole and used to push disk 108 down the ramp 110, overcoming the biasing force of spring 114. With disk 108 pushed down ramp 110, cable 106 can be retracted from channel 104a by pulling in the direction indicated by arrow 118. The drilled hole is then filled with a metal putty or filler corresponding to the material of the lock, which makes detection of the tampering virtually impossible. A second type of tampering can occur by drilling a hole into one of the sides of cable lock in an area 120 adjacent disk 108. The hole is drilled through outer member 101. A pin or other instrument is again used to push disk 108 down ramp 110 and thereby allow cable 106 to be retracted. A metal filler or putty is used to conceal the hole.
The aforementioned two methods of tampering with cable locks allow thieves to gain access to the contents of whatever the cable lock is protecting with minimal chance of detecting at what point, in the chain of movement of the goods, the theft occurs. This reduces the chances of identifying the thieves or recovering the goods. If a cargo is being shipped a great distance and passes through multiple warehouses, it may be impossible to tell in which of the multiple warehouses the theft or other tampering occurred. It can therefore be seen that a cable lock overcoming these and other disadvantages is very desirable.
According to one aspect of the present invention, a security lock is provided having an inner member and an outer member surrounding the inner member. The inner member defines a ramp on which a disk is positioned for movement along the ramp. A security insert having increased hardness, when compared to the outer member, is inserted between the outer and inner members. The security insert includes a pair of side panels dimensioned to surround the area adjacent the ramp on which the disk moves. The security insert further includes an end panel oriented generally perpendicular to the side panels and dimensioned to cover a portion of the inner member adjacent the upper end of the ramp.
According to another aspect of the present invention, a security lock is provided having an inner member that includes a first and a second end wall. The inner member defines an inclined ramp disposed between the first and the second wall. The ramp extends upwardly from the first end wall to the second end wall. A disk is positioned on the inclined ramp and biased up the ramp by one end of a spring. The other end of the spring is secured to the inner member. An outer shell fits over the inner member. the disk, and the spring. The outer shell and the inner member define a first and a second channel when the outer shell is placed over the inner member. A drill resistant member is disposed in the second end wall. The drill resistant member is made up of a material that is more resistive to drilling than the inner member.
According to another aspect of the present invention. a security lock is provided that comprises a body which defines at least one channel. A flexible member, such as a wire, cable, or the like, is attached at one end to the body and has another free end. A locking structure is defined in the body that allows the free end of the flexible member to be inserted into the channel in a first direction, but prevents extraction of the flexible member out of the channel in a reverse direction. A photo-luminescent coating is defined on or in the body which absorbs light energy while in the presence of ambient light and emits light energy while in the presence of ambient darkness.